Burning hydrocarbons in air produces NOx (mono-nitrogen oxides such as nitrogen oxide and nitrogen dioxide). NOx emissions are known to be deleterious for the ozone in the stratosphere. Atmospheric NOx also forms nitric acid, which contributes to acid rain. Because of these significant environmental concerns, it is highly desirable to reduce NOx emissions in the burning or combustion of hydrocarbon fuels. Furthermore, in some jurisdictions, environmental regulations limit the amount of NOx emissions that a burner may emit.